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United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOP TECHNOLOGIES TO PROTECT AIR QUALITY, MAINTAIN PRODUCTION EFFICIENCY & ENHANCE USE OF MANURE FROM SOUTHN GREAT PLAINS BEEF & DAIRY AG

Location: Livestock Nutrient Management

Title: Effects of increasing concentrations of wet distillers grains with solubles in steam-flaked corn-based diets of energy metabolism, carbon-nitrogen balance, and methane emissions of cattle

Authors
item Hales, Kristin
item Cole, Noel
item Macdonald, Jim -

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 16, 2012
Publication Date: February 1, 2013
Citation: Hales, K.E., Cole, N.A., MacDonald, J.C. 2013. Effects of increasing concentrations of wet distillers grains with solubles in steam-flaked, corn-based diets of energy metabolism, carbon-nitrogen balance, and methane emissions of cattle. Journal of Animal Science. 91:819-828.

Interpretive Summary: The growing ethanol industry in the Southern Great Plains has increased the use of wet distiller's grains with solubles (WDGS) in beef cattle diets. Few studies have used steam-flaked corn (SFC)-based diets to evaluate the effects of WDGS in finishing cattle diets, and there is little data pertaining to the net energy value of WDGS. In order to test the effects of feeding WDGS to beef cattle energy metabolism we fed steers four diets. Diets consisted of (1) SFC-based diet with 0% WDGS (SFC-0); (2) SFC-based diet with 15% WDGS (SFC-15); (3) SFC-based diet with 30% WDGS (SFC-30); and (4) SFC-based diet with 45% WDGS (SFC-45). Cottonseed meal and yellow grease were added or removed from the diets so that all four diets had the same concentrations of ruminally degradable protein and fat. As the dietary concentration of WDGS increased, fecal, urinary, and enteric methane (CH4) energy, as a proportion of energy intake increased. In contrast, digestible, metabolizable, and retained energy decreased as a proportion of energy intake as the dietary concentration of WDGS increased. Increasing concentration of WDGS in the diet did not affect heat production as a proportion of energy intake. Because of greater nitrogen (N) intake, total N excretion increased with increasing dietary WDGS concentration. Loss of carbon (C) in feces and CH4 increased as dietary WDGS concentration increased; whereas, carbon dioxide-C expired decreased as WDGS concentration increased. From these results, we conclude that CH4 production as a proportion of energy intake increases linearly when WDGS concentration in the diet is increased; however, dietary inclusion of WDGS at up to 45% seems to have no effect on heat production. The reason for the decrease in retained energy as WDGS increases in the diet is likely because of the increased fecal energy loss associated with feeding WDGS. Total N excretion, fecal C loss, and CH4-C expired increased linearly with increasing concentration of WDGS in the diet.

Technical Abstract: The use of wet distiller's grains with solubles (WDGS) in feedlot diets has increased in the Southern Great Plains as a result of the growing ethanol industry. Research evaluating the use of steam-flaked corn (SFC)-based diets in conjunction with WDGS is limited. Therefore, the effects of increasing concentrations of WDGS in a SFC-based diet on energy metabolism, carbon (C) and nitrogen (N) balance, and enteric methane (CH4) production were evaluated in Jersey steers using respiration calorimetry chambers. Four treatments were used in a Latin square design. Treatments consisted of: (1) SFC-based diet with 0% WDGS (SFC-0); (2) SFC-based diet with 15% WDGS (SFC-15); (3) SFC-based diet with 30% WDGS (SFC-30); and (4) SFC-based diet with 45% WDGS (SFC-45). Diets were balanced for degradable intake protein (DIP) and ether extract (EE) by the addition of cottonseed meal and fat. As a proportion of intake energy (IE), fecal, urinary, and CH4 energy increased linearly (P < 0.03) as WDGS concentration increased in the diet. In contrast, digestible energy (DE), metabolizable energy (ME), and retained energy decreased linearly (P < 0.01) as a proportion of IE as WDGS concentration increased. Increasing concentration of WDGS in the diet did not affect (P > 0.78) heat production as a proportion of IE. As a result of greater N intake, total N excretion increased linearly (P < 0.01) with increasing WDGS inclusion in the diet. Fecal C loss and CH4-C expired increased linearly (P < 0.01) when WDGS concentration increased in the diet; whereas, CO2-C expired decreased (linear, P = 0.05) as WDGS concentration increased. From these results, we conclude that CH4 production, as a proportion of IE, increases linearly (P < 0.01) when WDGS concentration in the diet is increased; however, dietary inclusion of WDGS at up to 45% seems to have no effect (P > 78) on heat production as a proportion of IE. The reason for a linear decrease in retained energy as WDGS increases in the diet is likely because of the increased fecal energy loss associated with feeding WDGS. Total N excretion, fecal C loss, and CH4-C expired increased linearly with increasing concentration of WDGS in the diet. Through feeding cattle near maintenance and at 2X maintenance we determined the net energy for maintenance (NEm) values for WDGS to be 2.54, 2.68, and 2.52 Mcal/kg when included at 15, 30, and 45%, respectively, in a SFC-based diet.

Last Modified: 10/25/2014
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